Historic earthquakes book-ended San Francisco in the last century, the resulting devastation dramatically different in 1989 than in 1906.

On Friday's 25th anniversary of the 1989 disaster, geologists insist more major quakes are inevitable. But they also say officials today are in a much better position to know where to send first responders thanks to a more elaborate system of sensors, better fault mapping and the communications prowess of the Internet, which hardly existed 25 years ago.

In terms of speed and reach, a seismic wave radiating from a quake's epicenter through the ground at two miles per second is no match for the Internet, where news of a quake can circumnavigate the globe multiple times in the same second.

The edge afforded by today's technology was demonstrated during the quake in Napa, Calif., on Aug. 24, according to Brad Aagaard, a research geophysicist at the U.S. Geological Survey in Menlo Park, Calif.

During that event, officials farther out from the epicenter had a five-second warning before they felt shaking. The magnitude-6 temblor was the largest earthquake to hit the Bay Area since 1989.

Five seconds doesn't seem like much time, but it could be sufficient for an official to dispatch emergency vehicles to a likely disaster area, shut off gas mains, stop trains or just stand in a doorway. Beyond municipal agencies, a new category of emerging mobile apps can warn the general public about imminent quaking at least 20 miles away in the same way a weather app does during severe weather.

Aagaard admits that when the South Napa quake struck at 3:20 a.m., not many subscribers to the Geological Survey's Shakecast and Shakemap's early warning systems were in front of their computers and trains were likely idle, but the system worked the way it was intended.

For sure, serendipity plays a large role in surviving an earthquake. Unlike a hurricane, which can be monitored by satellites, an earthquake is almost impossible to see coming.

One exception I encountered after the 1989 quake was a story conveyed by an engineer for a wind farm in the East Bay. He described a windsmith doing repairs atop a turbine who looked out and noticed something strange. Turbines in the distance were bending toward him like a field of wheat in the wind. He instinctively held on for dear life as the structure began to violently vibrate. According to the engineer, if the windsmith hadn't looked up, he might have been thrown from the tower.

Earthquakes leave an indelible impression on those who've been through one. Standing on Manhattan's Sixth Avenue with a friend from Southern California who had never been to New York before, her smile suddenly turned to dismay.

"Do you feel that?" she asked. Her relief was palpable when I told her it was the subway passing below.

I was fortunate that my San Francisco home was built on bedrock when the 1989 quake hit. My Sony Trinitron nudged its way precariously to the edge of its flimsy stand, but after 15 seconds of deafening noise that felt a lot longer at the time, the only evidence of what had happened was that the power had gone out and a tall stack of New York Times and San Francisco Examiners had fallen over.

A friend who lived in the Marina District wasn't so lucky. Her neighborhood was built on landfill that liquefied during the shake, turning her apartment building into the Leaning Tower of Pisa. Her belongings had to be rescued from the condemned building.

Sixty-three Bay Area people died in the 1989 quake, while though horrific was nothing compared to the 3,000 to 6,000 lost from collapsed buildings and the Great Fire that accompanied the 1906 earthquake. Some 490 city blocks with 25,000 buildings were destroyed and more than 250,000 people were left homeless.

So, why the discrepancy in outcomes?

First, a single digit difference on the Richter Scale between a 7.9 and 6.9 amounted to more than 30 times the energy being released during the earlier quake. The rupture itself was about 25 miles long in 1989 versus 300 in 1906. Also, according to Aagaard, the 1906 quake in San Francisco was felt for much longer — nearly a minute and a half versus about 15 to 20 seconds in 1989.

Building codes were much stricter and pipes more resilient at the culmination of the century than at the start. Thanks to new materials such as plastic, pipes and fittings were able to flex more than concrete conduits that simply broke.

The double whammy that proved so devastating in 1906 was that fires started by broken gas lines could not be put out because water mains had also ruptured. As a result of the 1906 catastrophe, an auxiliary water system was created that helped extinguish fires in the Marina District, among other places, before they could spread.

There was also a vast discrepancy in how information about the earthquakes was communicated. Millions of Americans had their eyes on Candlestick Park in San Francisco as the 1989 quake struck. The third game of the World Series was about to begin, and — you can't make this stuff up — pitted the San Francisco Giants against their across-Bay rivals, the Oakland A's.

The rest of America saw what happened instantly. But in 1906, telegraphs and the fledging phone system within the city stopped working. Television wouldn't be invented on Green Street in San Francisco by Philo Farnsworth for another 21 years. Fortunately, newspapers spread the word much sooner.

New York-based writer/editor Michael Antonoff covers technology and the media.